What is the greatest common factor of $30$ and $5$ ? Another way to say this is: $\operatorname{gcf}(30, 5) = {?}$
Explanation: The greatest common factor is the largest number that is a factor of both $30$ and $5$ The factors of $30$ are $1$ $2$ $3$ $5$ $6$ $10$ $15$ , and $30$ The factors of $5$ are $1$ and $5$ Thus, the greatest common factor of $30$ and $5$ is $5$. $\operatorname{gcf}(30, 5) = 5$